THE MOSQUITO 73 



— ' usually the octave ' of the one produced 

 by the wing vibrations — is unexplained by 

 this view. It is, however, easily explicable if 

 such a stridulating organ as we have described 

 at the base of the wing in Anopheles maculi- 

 pennis be found in other Diptera and in 

 Hymenopterous insects. 



In our paper Mr. Wilson and I thought 

 it well to figure the upper surface of the 

 halter . as seen under a high magnification. 

 The drawing showed the hinge on which the 

 halter quivers — and certain basal papillae, as 

 Weinland ^ calls them. There is little doubt 

 that the main function of the halteres is that 

 of balancing and orientating the insect. They 

 may, however, have a secondary function ; 

 in some flies they are known to vibrate with 

 extreme rapidity. It is just possible that 

 in these rapid vibrations the papillae of the 

 concave surface rubbing against those of the 

 convex basal plate may produce a note. As 

 long ago as 1764 von Gleichen-Russworm ^ 

 observed that when the halteres of the common 

 house-fly are removed the volume of the 

 buzzing diminished. This, however, in all 

 probability is due to the diminished activity 

 of the wings. On the other hand. Professor 

 J. Stanley Gardiner informs us that he has 



1 Zeit. f. ivissensch. Zool. (1891), li, p. 55. 



2 Geschichte der gemeinen Stubenfliege. Nuremberg, 1764. 



